openslx/kernel-qcow2-linux.git - In-kernel qcow2 (Kernel part)

	Commit message (Expand)	Author	Age	Files	Lines
*	Squashfs: update comment removing reference to zlib only	Phillip Lougher	2012-03-10	1	-1/+2
*	Squashfs: update email address	Phillip Lougher	2011-05-26	1	-1/+1
*	squashfs: fix use of uninitialised variable in zlib & xz decompressors	Phillip Lougher	2011-01-26	1	-0/+8
*	Squashfs: move squashfs_i() definition from squashfs.h	Phillip Lougher	2011-01-13	1	-1/+0
*	squashfs: fix potential buffer over-run on 4K block file systems	Phillip Lougher	2010-04-25	1	-3/+2
*	Squashfs: add a decompressor framework	Phillip Lougher	2010-01-20	1	-1/+2
*	Squashfs: factor out remaining zlib dependencies into separate wrapper file	Phillip Lougher	2010-01-20	1	-1/+0
*	Squashfs: move zlib decompression wrapper code into a separate file	Phillip Lougher	2010-01-20	1	-70/+4
*	Squashfs: Valid filesystems are flagged as bad by the corrupted fs patch	Phillip Lougher	2009-03-12	1	-17/+4
*	Squashfs: Fix oops when reading fsfuzzer corrupted filesystems	Phillip Lougher	2009-03-05	1	-2/+11
*	Squashfs: block operations	Phillip Lougher	2009-01-05	1	-0/+274

/* * Squashfs - a compressed read only filesystem for Linux * * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008 * Phillip Lougher <phillip@squashfs.org.uk> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2, * or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. * * block.c */ /* * This file implements the low-level routines to read and decompress * datablocks and metadata blocks. */ #include <linux/fs.h> #include <linux/vfs.h> #include <linux/slab.h> #include <linux/string.h> #include <linux/buffer_head.h> #include "squashfs_fs.h" #include "squashfs_fs_sb.h" #include "squashfs.h" #include "decompressor.h" /* * Read the metadata block length, this is stored in the first two * bytes of the metadata block. */ static struct buffer_head *get_block_length(struct super_block *sb, u64 *cur_index, int *offset, int *length) { struct squashfs_sb_info *msblk = sb->s_fs_info; struct buffer_head *bh; bh = sb_bread(sb, *cur_index); if (bh == NULL) return NULL; if (msblk->devblksize - *offset == 1) { *length = (unsigned char) bh->b_data[*offset]; put_bh(bh); bh = sb_bread(sb, ++(*cur_index)); if (bh == NULL) return NULL; *length |= (unsigned char) bh->b_data[0] << 8; *offset = 1; } else { *length = (unsigned char) bh->b_data[*offset] | (unsigned char) bh->b_data[*offset + 1] << 8; *offset += 2; if (*offset == msblk->devblksize) { put_bh(bh); bh = sb_bread(sb, ++(*cur_index)); if (bh == NULL) return NULL; *offset = 0; } } return bh; } /* * Read and decompress a metadata block or datablock. Length is non-zero * if a datablock is being read (the size is stored elsewhere in the * filesystem), otherwise the length is obtained from the first two bytes of * the metadata block. A bit in the length field indicates if the block * is stored uncompressed in the filesystem (usually because compression * generated a larger block - this does occasionally happen with compression * algorithms). */ int squashfs_read_data(struct super_block *sb, void **buffer, u64 index, int length, u64 *next_index, int srclength, int pages) { struct squashfs_sb_info *msblk = sb->s_fs_info; struct buffer_head **bh; int offset = index & ((1 << msblk->devblksize_log2) - 1); u64 cur_index = index >> msblk->devblksize_log2; int bytes, compressed, b = 0, k = 0, page = 0, avail; bh = kcalloc(((srclength + msblk->devblksize - 1) >> msblk->devblksize_log2) + 1, sizeof(*bh), GFP_KERNEL); if (bh == NULL) return -ENOMEM; if (length) { /* * Datablock. */ bytes = -offset; compressed = SQUASHFS_COMPRESSED_BLOCK(length); length = SQUASHFS_COMPRESSED_SIZE_BLOCK(length); if (next_index) *next_index = index + length; TRACE("Block @ 0x%llx, %scompressed size %d, src size %d\n", index, compressed ? "" : "un", length, srclength); if (length < 0 || length > srclength || (index + length) > msblk->bytes_used) goto read_failure; for (b = 0; bytes < length; b++, cur_index++) { bh[b] = sb_getblk(sb, cur_index); if (bh[b] == NULL) goto block_release; bytes += msblk->devblksize; } ll_rw_block(READ, b, bh); } else { /* * Metadata block. */ if ((index + 2) > msblk->bytes_used) goto read_failure; bh[0] = get_block_length(sb, &cur_index, &offset, &length); if (bh[0] == NULL) goto read_failure; b = 1; bytes = msblk->devblksize - offset; compressed = SQUASHFS_COMPRESSED(length); length = SQUASHFS_COMPRESSED_SIZE(length); if (next_index) *next_index = index + length + 2; TRACE("Block @ 0x%llx, %scompressed size %d\n", index, compressed ? "" : "un", length); if (length < 0 || length > srclength || (index + length) > msblk->bytes_used) goto block_release; for (; bytes < length; b++) { bh[b] = sb_getblk(sb, ++cur_index); if (bh[b] == NULL) goto block_release; bytes += msblk->devblksize; } ll_rw_block(READ, b - 1, bh + 1); } if (compressed) { length = squashfs_decompress(msblk, buffer, bh, b, offset, length, srclength, pages); if (length < 0) goto read_failure; } else { /* * Block is uncompressed. */ int i, in, pg_offset = 0; for (i = 0; i < b; i++) { wait_on_buffer(bh[i]); if (!buffer_uptodate(bh[i])) goto block_release; } for (bytes = length; k < b; k++) { in = min(bytes, msblk->devblksize - offset); bytes -= in; while (in) { if (pg_offset == PAGE_CACHE_SIZE) { page++; pg_offset = 0; } avail = min_t(int, in, PAGE_CACHE_SIZE - pg_offset); memcpy(buffer[page] + pg_offset, bh[k]->b_data + offset, avail); in -= avail; pg_offset += avail; offset += avail; } offset = 0; put_bh(bh[k]); } } kfree(bh); return length; block_release: for (; k < b; k++) put_bh(bh[k]); read_failure: ERROR("squashfs_read_data failed to read block 0x%llx\n", (unsigned long long) index); kfree(bh); return -EIO; }